1. Field of the Invention
The present invention relates to a method to control the heating of heating elements, particularly heating elements in a seat of an automotive vehicle. The invention operates in a progressive manner and is adapted to controlling said heating elements' state at all times.
2. Description of the Related Art
U.S. Pat. No. 6,252,208 issued on Jun. 26, 2001 to Topp teaches a method and a circuit for controlling the heating current of a seat heater according to the temperature. The same reference teaches a control system based on varying the control signals applied to the heating element from a fixed table saved in ROM memory, which relates application time values of said signals with temperature values monitored through a temperature sensor arranged in said heater. Additionally, U.S. Pat. No. 6,252,208 does not take into account that the heating elements can be different or, especially, have different physical features throughout their useful life, and that these can be modified, particularly in the case of their application in the seat of an automotive vehicle. Their features and performance can significantly vary according to the weight, position and span of the person using the seat and also according to the surrounding environment.
U.S. Pat. No. 3,768,156 issued on Oct. 30, 1973 to Caird et al teaches a method for manufacturing heating panels based on the use of electric conducting polymers, to form a flexible resistive and electricity-conducting element. A voltage is applied through two electrodes connected to each of said elements with the object of heating the heating panel. This reference, although it indicates that the temperature of the panel could be controlled by including a thermostat, does not teach a method for carrying out said control.
There is still a need for a reliable and practical method for controlling the heating of such heating elements. It is therefore desirable to provide a more reliable method for controlling the temperature of said heating elements. The present invention takes into account the heating elements' possible variations of form, depending on the pressure applied to it and the distribution thereof. The present invention also addresses the variation of the heating elements' resistive and conductive features, including those dependent on external parameters such as the temperature of the area in which the heating element is arranged. The present invention also addresses the fact that different materials can be used and arranged such that they form different structures, thus forming different heating elements which obviously will not react in the same way to the same control signal.